The main idea of the limbo inception is the possibility to get stuck inside a deeper-level dream. Another way to explain it is if you entered somebody else's dream and you got down to a deeper level (a dream inside a dream) you must beware not to die. As if you die in a deeper-level dream, you get into a state of a limbo and will not be able to wake up. That means you will stay in the deeper level of dream forever. Fortunately, this is just a theory made by the amazing Inception movie.